Endstone glitch

I am reporting this for my friend. He found a glitch with Endstone. The top looks like Warped Hyphae but the rest looks like endstone. And from afar, the Warped Hyphae looking top will become a red square and a blue square diagonal from each other, one purple square, and a dark black square. He has updated his graphics card and has the newest updates of his computer, so he doesn't know what to do.